Gas turbine



Oct 2, 1951 T. w. MILLNs 2,569,898

GAS TURBINE Filed Jan. 26, 1949 2 Sheets-Sheet l Oct. 2, 1951 2 Sheets-Sheet 2 Filed Jan. 26, 1949 III' Patented Oct. 2, 1951 UNITED STATES PATENT OFFICE GAs TURrNE* Terence "William Millns, London, England, yas" signor to Rotax Limited, London, `England i Application January 26, 1949,`Serial No.'72,953 In Great Britain February '3, 1948 removed to expose the controlling means asso- .ciated with the motive fluid inlet nozzles.

Figure 3 is a fragmentary sectional plan illustrating the portion of the controlling means associated with one of the nozzles and an adjacent `portion of the rotor.

`supported in the housing by bearings f, g, an annular nozzle plate h, which has formed on it a laterally extending .flange i which surrounds and is closely adjacent to the rotor blading, the inner periphery of this plate being lined with a ring y' of friction material. Within the plate h there is mounted a clutch disc 7c which is secured to the adjacent face of the rotor, and has formed on it a laterally projecting and exible peripheral flange m, which is split radially at a number of positions (see Figure 2) to enable it to expand into contact with the friction ring y' under the action of centrifugal force when the speed of the rotor exceeds a predetermined amount. When this speed is attained, the clutch lc by its action on the nozzle plate h imparts to the latter an angular movement which is restricted to an appropriate amount in any convenient manner, as, for-example, by a stop peg n secured to the housing and extending across `a notch in the flange z' of said plate.

Alongside the movable nozzle plate h there is mounted in the housing a xed nozzle plate o, this being held in position by the adjacent end cover p of the housing in which are formed (for example four) equi-spaced motive fluid passages q extending radially from a common inlet r.

The plane of section of the View shown in Figure 1 does not admit of the representation therein of the nozzle passages which lead from the passages q to the rotor blading, but one such passage is clearly shown in Figure 3, which will now be described in conjunction with Figures 1 and 2.

In thefsidepf the fixed `the Amovable -nozzle plate h is formed an an- ,nularrecess s which is open adjacent to its A,outer periphery to by-pass outlet passages t in nozzle plate o adjacent vto the :housing leading to the main outlet u. Also `in the `fixed nozzle plate o are formed (for examplegfour) motive iiuid passages c each of which at one end is open to the associated inlet passages a. Each such passage extends through a plate `w secured to the iixed plate o, and immediately oppositethe discharge endof the passage 'v there is formed in the movable plate h an orifice o; through.v which the motive fluid can pass to the rotor blading eiafter crossing the .recess s. Further, there is secured to the plate h adjacent to one end Vof each oriiice :t a rib y which abuts against or lies closely adjacent to the outer face of the plate w.

The mode of action is as follows: Sio long as the rotor ,is rotating at a predetermined speed, the nozzle plates occupy the relative positions shown in Figure 3. But in the event of that speed being exceeded, the effect of centrifugal force on the expansible periphery m of the clutch part 7c causes it to engage the friction ring :i and move the plate h, (in the direction of the arrow, Figure 3) to an extent permitted by the stop peg n and so cause each of the ribs y to be moved to the opposite side of the orifice in the plate w. The motive fluid flowing through the passages n to the blading e is thereby intercepted by the plate h and diverted radially outwards across the recess s to the by-pass passages t, thus putting the rotor out of action.

To enable the plate h to resume its normal position after the speed of the rotor has become suliciently reduced to release the clutch member 7c, any convenient spring or equivalent means may be used. In one arrangement a plurality of springs e (of which one is shown in Figure 1) are arranged in the housing in connection with the plate h, and adapted to return it to its initial position after release by the clutch member. It is desirable, however, that return of the plate h to its initial position after release sha-ll not ocour until the flow of motive gas through the passages 'v has been interrupted, or sufficiently reduced, and this requirement is met by the pressure o1 the diverted gas streams against one side of the ribs y, this pressure being suicient to hold the plate h against the `action of the springs until the gas flow has been sufciently reduced.

The particular example above described is especially suitable for use as a part of an enginestarting machine, the turbine rotor being driven by gas supplied from an explosive charge contained in a cartridge. In such use the automatic return of the movable nozzle plate (in the event of its displacement as a result of excessive speed of the rotor), occurs at or towards the end of the discharge from the cartridge, in readiness for actuation by a successive cartridge discharge.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A gas turbine comprising in combination a rotor having peripheral blading, a housing containing the rotor, a movable nozzle member of annular form mounted in the housing at one side of the rotor, and capable of angular movement between a normal position in which motive fluid can flow therethrough to the rotor blading, and another position in which motive uid is deflected away from the rotor blading by the nozzle mem- Aber, and a clutch disc situated within the an- Anular nozzle member and secured to the rotor,

the clutch disc having a laterally projecting peripheraliiange which issplit transversely at a plurality of positions to render it resilient and capable of outward radial deflection under the action of centrifugal force into frictional engagement with the annular nozzle member, so that the latter is displaceable by the clutch disc to the position for deflecting the motive fluid away from the rotor blading when the speed of the rotor exceeds a predetermined limit.

. I2. A gas turbine comprising in combination a rotor having peripheral blading, a housing containing the rotor, a stationary nozzle member in the housing at one side of the rotor and formed with passages for motive fluid, a, movable annular nozzle member mounted in the housing between'the rotor and the stationary nozzle member, and capable of angular movement between a normal position in which motive fluid from the .passages in the stationary nozzle member can flow through the movable nozzle member to the rotor blading, and another position in which motive uid from the said passages is deflected away from the rotor blading by the movable nozzle member, a clutch disc situated Within the movable nozzle member and secured to the rotor, the clutch disc having a laterally projecting peripheral flange which is split transversely at a plurality of positions to render it resilient and capable of outward radial deflection under the action of centrifugal force, and friction means through which the flange on the clutch disc is engageable with the movable nozzle member to enable the latter to be displaced by the clutch disc to the positiony for deflecting the motive fluid away from the rotor blading ywhen the speed of the rotorexceeds a predetermined limit.

3. A gas turbine as claimed in claim 1 and having spring means for automatically returning the movable nozzle member to its normal position when the speed of the rotor is reduced sulic'iently to release the flange onV the clutch memberfrom the movable nozzle member, and abutments provided on the movable nozzle member at positions where the motive fluid can impinge thereon and thereby temporarily hold the movable nozzle member in its displaced position.

TERENCE WILLIAM MILLNs.

REFERENCES CITED The following references are ofV record lin the file of this patent:

UNITED STATS PATENTS Y 

